汽车系统构造英文版-Lesson14SuspensionSystem

ID CHS ENU pnFrom LEVEL 1汽车悬架suspension汽车悬架(su1 2螺纹衬套screw bushi汽车悬架(su1 3螺旋弹簧coil spring汽车悬架(su1 4麦弗逊式MacPherson 汽车悬架(su1 5膜式空气弹簧diaphragm t汽车悬架(su1 6磨擦式减振器frictional 汽车悬架(su1 7囊式空气弹簧bellow type汽车悬架(su1 8扭矩套管torque tube汽车悬架(su1 9扭矩套管式torque tube汽车悬架(su1 10平横臂equalizer汽车悬架(su1 11平衡杆stabilizer 汽车悬架(su1 12平衡悬架equalizing 汽车悬架(su1 13平衡轴trunnion sh汽车悬架(su1 14平衡轴支座trunnion ba汽车悬架(su1 15全椭圆形弹簧full ellipt汽车悬架(su1 16三点悬架three-point汽车悬架(su1 17上控制臂upper contr汽车悬架(su1 18上弯式梁架upswept fra汽车悬架(su1 19上悬架臂upper suspe汽车悬架(su1 20上置板簧式over slung 汽车悬架(su1 21双横臂式double -wis汽车悬架(su1 22双横臂式double with汽车悬架(su1 23双气室油气弹簧double cham汽车悬架(su1 24双纵臂式double trai汽车悬架(su1 25双纵臂式double-trai汽车悬架(su1 26四点悬架four-point 汽车悬架(su1 27四分之三椭圆形弹簧three quart汽车悬架(su1 28四分之一椭圆形弹簧quarter ell汽车悬架(su1 29四连杆式four link t汽车悬架(su1 30筒式减振器telescopic 汽车悬架(su1 31下控制臂lower contr汽车悬架(su1 32下置板簧式under slung汽车悬架(su1 33限位块limiting st汽车悬架(su1 34橡胶衬套rubber bush汽车悬架(su1 35橡胶弹簧rubber spri汽车悬架(su1 36橡胶弹簧式rubber spri汽车悬架(su1 37橡胶液体弹簧式hydro-rubbe汽车悬架(su1 38斜臂oblique arm汽车悬架(su1 39悬臂弹簧cantilever 汽车悬架(su1 40悬架suspension汽车悬架(su1 41悬架臂suspension 汽车悬架(su1 42悬架系suspension 汽车悬架(su1 43压杆strut bar汽车悬架(su1 44摇臂式减振器lever type 汽车悬架(su1 45液体弹簧hydraulic s汽车悬架(su1 46液体弹簧hydraulic s汽车悬架(su1 47液体弹簧式hydraulic s汽车悬架(su1 48液压减振器dydraulic s汽车悬架(su1 49油气弹簧hydro-pneum汽车悬架(su1 50油气弹簧式hydro-pneum汽车悬架(su1 51油压缓冲器hydraulic b汽车悬架(su1 52整体车架unitized fr汽车悬架(su1 53支撑杆strut bar汽车悬架(su154支撑梁support bea汽车悬架(su1 55制动反应杆brake react汽车悬架(su1 56烛式sliding pil汽车悬架(su1 57纵臂trailing ar汽车悬架(su1 58纵向钢板弹簧longitudina汽车悬架(su1 59纵向推力杆longitudina汽车悬架(su1 60纵置板簧式parallel le汽车悬架(su1 61组合式悬架combination汽车悬架(su1 62（车身）高度阀levelling v汽车悬架(su1 63U 型螺栓U bolt汽车悬架(su1 64半径杆radius rod汽车悬架(su1 65半椭圆形弹簧half-ellipt汽车悬架(su1 66臂轴arm shaft汽车悬架(su1 67变截面弹簧tapered spr汽车悬架(su1 68部件assembly an汽车悬架(su1 69车架auxiliary t汽车悬架(su1 70充气减振器gas-filled 汽车悬架(su1 71单横臂式singe trail汽车悬架(su1 72单横臂式single tran汽车悬架(su1 73单片式钢板弹簧single leaf汽车悬架(su1 74单气室油气弹簧single cham汽车悬架(su1 75单斜臂式single obli汽车悬架(su1 76弹簧架spring brac汽车悬架(su1 77弹簧静挠度spring stat汽车悬架(su1 78弹簧卷耳spring eye汽车悬架(su1 79弹簧跳动间隙bump cleara汽车悬架(su1 80弹簧中心距distance be汽车悬架(su1 81弹簧主片spring leaf汽车悬架(su1 82底盘弹簧chassis spr汽车悬架(su1 83地面弹簧载荷量spring capa汽车悬架(su1 84第迪安式De Dion typ汽车悬架(su1 85垫上弹簧载荷量spring capa汽车悬架(su1 86动力减振器dynamic sho汽车悬架(su1 87独立悬架independent汽车悬架(su1 88短型车架stub frame汽车悬架(su1 89多片式钢板弹簧muotileaved汽车悬架(su1 90发动机支架engine moun汽车悬架(su1 91非独立悬架rigid axle 汽车悬架(su1 92非对称钢板弹簧unsymmetric汽车悬架(su1 93分开式车身和车架separated b汽车悬架(su1 94负荷调平式减振器load -level汽车悬架(su1 95副钢板弹簧auxiliary s汽车悬架(su1 96钢板弹簧leaf spring汽车悬架(su1 97钢板弹簧衬套leaf spring汽车悬架(su1 98钢板弹簧吊耳leaf spring汽车悬架(su1 99钢板弹簧销leaf spring汽车悬架(su1 100钢板弹簧中心螺栓leaf spring汽车悬架(su1 101横臂transverse 汽车悬架(su1 102横向推力杆lateral rod汽车悬架(su1 103横向稳定器stabilizer 汽车悬架(su1 104横置板簧式transversal汽车悬架(su1 105滑板sliding pla汽车悬架(su1 106滑动座sliding sea汽车悬架(su1 107缓冲块buffer stop汽车悬架(su1108簧上质量sprung weig汽车悬架(su1 109簧下质量unsprung we汽车悬架(su1 110减振器shock absor汽车悬架(su1 111减振器进油阀shock absor汽车悬架(su1 112减振器示功图damper indi汽车悬架(su1 113减振器卸荷阀shock absor汽车悬架(su1 114减振器液damper flui汽车悬架(su1 115金属弹簧式metal sprin汽车悬架(su1 116可变刚度悬架variable ra汽车悬架(su1 117可调减振器adjustable 汽车悬架(su1 118空气弹簧air spring汽车悬架(su1 119空气弹簧式air spring 汽车悬架(su1 120控制臂control arm汽车悬架(su1 121拉杆tension rod汽车悬架(su1。

The Complexities of Automobile Construction The automobile, a product of technological innovation and engineering genius, has transformed our world. Its history, rich with pivotal moments and influential innovators, began in the late 19th century and has since become a ubiquitous fixture of modern life. This article delves into the intricacies of automobile construction, highlighting key components, systems, and recent technological advancements.Essential Components of an AutomobileAn automobile is composed of numerous parts, each serving a specific function. The engine, often considered the heart of the car, generates power. The chassis supports the body and houses the mechanical components. The seats, along with the interior, provide a comfortable environment for occupants.Engine Systems: The Heart of the MatterEngines are classified as internal combustion (IC) or external combustion (EC). IC engines, such as gasoline and diesel engines, are more common in modern automobiles. They operate by mixing fuel with air, igniting the mixture, and harnessing the resulting expansion to create power. Diesel engines are more efficient but emit more noise and pollution. Gasoline engines, on the other hand, offer smoother operation but are less fuel-efficient.Chassis Systems: The Backbone of the VehicleThe chassis supports the car's structure and contains critical systems like the suspension and braking. The suspension system absorbs road shocks, improving ride quality and tire contact with the road. The braking system converts kinetic energy into heat,slowing or stopping the car. Both systems are carefully designed to offer a balance between performance and comfort.Seating and Interior: Comfort and ErgonomicsSeats are designed to offer support and comfort, often with the help of ergonomic principles. Materials like leather, vinyl, and fabric are chosen for durability, comfort, and aesthetics. The interior, which includes dashboards, door panels, and carpeting, is equally important in creating a pleasant driving environment.Emerging Technologies in Automotive ConstructionRecent technological advancements have revolutionized the automotive industry. Autonomous vehicles, enabled by advances in sensor technology, artificial intelligence, and computer vision, promise safer, more efficient driving. Electric and hybrid vehicles, driven by batteries and alternative fuels, are becoming increasingly popular due to their environmental benefits.Environmental Considerations in Automotive DesignConsumers are increasingly concerned with the environmental impact of their purchases. Automobile manufacturers are responding with more fuel-efficient vehicles and eco-friendly materials. Consumers can further contribute by selecting vehicles with low emissions and recycling old cars.ConclusionUnderstanding the intricacies of automobile construction is essential for appreciating the engineering feats that underlie our modern way of life. It also informs responsible consumer choices, vital for sustainable development. As technology continues to evolve, the future of the automobile promises to be even more exciting and innovative.。

汽车构造英汉对照词汇总论汽车automobile拖拉机tractor铁路机车locomotive有轨电车tram无轨电车trolley军用车辆military vehicle 蒸汽机steam engine煤气机gas engine汽油机gasoline engine国民经济national economy 国内生产总值(GDP) Gross Domestic Production全拆散(CKD) Completely Knock Down半拆散(SKD) Semi-Knock Down改革开放reform and opening技术引进technical import 国产化localization支柱产业pillar estate轿车car客车bus, coach货车truck, lorry公路用车road vehicle非公路用车off-road vehicle发动机engine机体engine body曲柄连杆机构crank-connecting rod mechanism配气机构valve timing mechanism供给系fuel supply system 冷却系cooling system润滑系lubricating system 点火系ignition system起动系starting system底盘chassis传动系power train 离合器clutch变速器gear box传动轴propeller shaft驱动桥drive axle行驶系running gear车架frame悬架suspension前轴front axle桥壳axle housing车轮wheel转向系steering system转向盘steering wheel转向器steering gear转向传动装置steeringlinkage助力装置power assistingdevice制动系braking system控制装置control device供能装置power supplydevice传动装置transfer device制动器brake车身body车前板制件front endpanels车身壳体body shell车门door车窗window附属装置auxiliary device货箱carrying platform发动机前置后轮驱动(FR)front engine rear drive发动机前置前轮驱动(FF)front engine front drive发动机后置后轮驱动(RR)rear engine rear drive发动机中置后轮驱动(MR)midship engine rear drive全轮驱动(nWD) all wheeldrive驱动力tractive force阻力resistance滚动阻力rolling resistance空气阻力air resistance,drag上坡阻力gradientresistance附着作用adhesion附着力adhesive force附着系数coefficient ofadhesion第一章发动机工作原理二冲程发动机two strokeengine四冲程发动机four strokeengine水冷发动机water cooledengine风冷发动机air cooledengine上止点(UDP) upper deadpoint下止点(LDP) lower deadpoint活塞行程stroke汽缸直径bore工作容积working volume排量swept volume,displacement进气行程intake stroke压缩行程compressionstroke压缩比compression ratio做功行程working stroke爆燃，敲缸detonation,knock排气行程exhaust stroke示功图indicating diagram汽缸体cylinder block汽缸盖cylinder head油底壳oil sump活塞piston连杆connecting rod曲轴crankshaft飞轮flywheel进气门intake valve排气门exhaust valve挺柱tappet推杆push rod摇臂rocker凸轮轴camshaft正时齿轮timing gear燃油箱fuel tank燃油泵fuel pump汽油滤清器gasoline filter 化油器carburetor空气滤清器air cleaner进气管intake manifold排气管exhaust manifold火花塞spark plug点火线圈ignition coil断电器breaker蓄电池storage battery发电机generator水泵water pump散热器radiator风扇fan放水阀drain valve水套water jacket分水管distributive pipe机油泵oil pump集滤器suction filter限压阀relief valve润滑油道oil passage机油滤清器oil filter机油冷却器oil cooler起动机starting motor有效功率effective power有效转矩effective torque 燃油消耗率specific fuel consumption发动机转速特性enginespeed characteristic节气门开度throttlepercentage部分特性partial characteristic外特性outer characteristic 第二章曲柄连杆机构汽缸套cylinder sleeve, cylinder liner 发动机支承enginemounting活塞顶piston top活塞头部piston head活塞裙piston skirt开槽slot活塞环piston ring气环compression ring油环oil ring环槽groove活塞销piston pin主轴承main bearing主轴承盖main bearing cap主轴瓦main shell连杆轴承big end bearing连杆盖big end cap起动爪cranking claw带轮pulley平衡重counter weight发火顺序firing order扭振减振器torsionalvibration damper第三章配气机构顶置气门(OHV) OverHead V alve顶置凸轮轴(OHC) OverHead Camshaft单顶置凸轮轴(SOHC)Single Over Head Camshaft双顶置凸轮轴(DOHC)Dual Over Head Camshaft多气门发动机multi-valveengine气门间隙valve clearance配气相位timing phase气门杆valve stem气门座valve seat气门导管valve guide气门弹簧valve spring第四章汽油机供给系可燃混合气combustionmixture消声器silencer, muffler汽油gasoline, petrol分馏distil蒸发性evaporatingproperty热值heat value抗爆性anti-knock property辛烷值(RON) ResearchOctane Number过量空气系数coefficientof excessive air理论混合气theoreticalmixture稀混合气thin mixture浓混合气thick mixture主供油系统main supplysystem怠速系统idle system加浓系统thickening system加速系统acceleratingsystem浮子float浮子室float chamber针阀needle valve量孔metering jet阻风门choke滤芯filter cartridge沉淀杯sediment cup泵膜pump diaphragm油浴式oil bath type石棉垫a**estos pad预热pre-heating汽油直接喷射gasolinedirect injection电控electronic control多点喷射muti-pointinjection单点喷射single pointinjection电路控制circuit control分电器信号distributorsignal空气流量信号airflowsignal冷却水温信号watertemperature signal第五章柴油机供给系输油泵transfer pump喷油泵fuel injection pump 高压油管high pressure fuelpipe发火性ignition property黏度viscosity凝点condensing point备燃期pri-combustion period速燃期rapid combustion period缓燃期slow combustion period燃烧室combustion chamber统一燃烧室united chamber 球形燃烧室ball shape chamber涡流室turbulence chamber 预燃室pri-combustion chamber喷油器injector精密偶件precise couple柱塞plunger出油阀delivery valve调速器governor两速调速器two speed governor全速调速器full speed governor定速调速器fixed speedgovernor综合调速器combined governor气动调速器pneumatic governor机械离心式调速器mechanical centrifugal governor复合式调速器complex governor喷油提前角调节装置advancer 飞块flyweight联轴节coupling粗滤清器primary filter细滤清器secondary filter涡轮增压器turbocharger中间冷却器intermediatecooler第七章冷却系节温器thermostat防冻液anti-freezing liquid补偿水桶compensationreservoirV-带V belt百叶窗shutter大循环big circulation小循环small circulation散热翅片fins第八章润滑系润滑剂lubricant压力润滑pressurelubrication飞溅润滑splash lubrication润滑脂grease机油压力传感器oilpressure sensor油封oil seal旁通阀bypass valve机油散热器oil cooler机油尺dip stick加机油口oil filler曲轴箱通风crankcaseventilation第九章点火系一次绕组primary winding二次绕组secondarywinding热敏电阻heat sensitiveresistance点火提前ignition advance分电器distributor活动触点moving contact固定触点fixed contact分火头distributor rotor arm电容器condenser点火提前装置ignitionadvancer离心式点火提前装置centrifugal ignition advancer真空式点火提前装置vacuum ignition advancer辛烷值校正器octanenumber rectifier中心电极central electrode侧电极side electrode瓷绝缘体ceramic insulator跳火间隙spark gap半导体点火系semi-conductor ignitionsystem晶体管transistor二极管diode三极管triode无触点点火系non-contactignition system霍尔效应Hall effect正极板anode负极板cathode隔板separator电解液electrolyte蓄电池格battery cell接线柱terminal电缆cable硅整流交流发电机siliconrectified A.C. motor转子rotor定子stator电刷brush风扇叶轮fan blade电压调节器voltageregulator第十章起动系手摇起动cranking电热塞electric heater plug串激直流发电机serialwound D.C. motor起动齿圈starter ring电磁操纵机构electro-magnetic control第十一章新型发动机三角活塞triangular piston 转子发动机rotary engine 自转rotary motion, rotation 公转orbit motion轨迹trajectory齿轮gear齿圈ring gear往复零件reciprocal parts动平衡dynamic balance燃气涡轮发动机gas turbine第十二章汽车传动系机械式传动系mechanical transmission液力机械式传动系hydro-mechanical transmission静液式传动系static-hydraulic transmission 电力式传动系electrical transmission自动式传动系automatic transmission减速reduction可变速比variable ratios有级变速definite ratios无级变速indefinite ratios 无级变速器(CVT) Continuously V ariable Transmission一般布置general layout发动机横置lateral engine positioning分动器transfer case, transfer box第十三章离合器接合柔和smooth engagement分离彻底thorough separation过载overload摩擦表面friction surface摩擦衬片friction liner 毂hub主动部分driving part从动部分driven part花键spline压盘pressure plate离合器盖cover plate分离杠杆release lever分离套筒release sleeve分离轴承release bearing主缸master cylinder工作缸working cylinder分离叉release fork间隙调整clearanceadjustment打滑slip踏板pedal踏板自由行程pedal freestroke踏板工作行程pedalworking stroke铆钉，铆接rivet双片离合器dual disc clutch中央弹簧离合器centralspring clutch膜片弹簧离合器diaphragmspring clutch非线性non-linear第十四章变速器与分动器输入轴（第一轴）input shaft,drive shaft输出轴（第二轴）output shaft,main shaft中间轴counter shaft倒挡轴reverse gear shaft常啮合constant mesh低速挡low gear高速挡high gear最高速挡top gear空挡neutral gear一挡the first gear二挡the second gear三挡the third gear倒挡reverse gear直接挡direct gear超速挡overdrive动力输出power take-off换挡shift啮合套sliding sleeve同步器synchronizer同步锥面synchro cone变速杆shifting lever手柄handle球铰链ball joint换挡拨叉shifting fork自锁self-lock互锁inter-lock变速驱动桥transaxle加力挡low gear第十五章液力机械传动液力偶合器hydrauliccoupling泵轮impeller涡轮turbine叶片blade液力变矩器torqueconverter导轮stator行星齿轮系planetary gearsystem太阳轮sun gear行星轮planet pinion行星架planet carrier齿圈ring gear第十六章传动轴万向节universal joint,U-joint十字轴式万向节Cardantype U-joint叉子yoke, fork十字轴spider, center cross滚针轴承needle bearing滑脂嘴（油嘴）lubricatingfitting, nipple等角速constant angularvelocity双联式万向节dual Cardantype U-joint球叉式万向节Weiss typeU-joint球笼式万向节Rzeppa typeU-joint星形套inner race housing 球形壳outer race shell保持架，球笼retainer, ball cage挠性万向节flexible U-joint无缝钢管seamless steel tube第十七章驱动桥主减速器final drive主动（小）齿轮drive pinion从动（大）齿轮ring gear 伞齿轮bevel gear双曲面齿轮hypoid gear单级减速single reduction 双级减速double reduction 贯通式主减速器penetrable final drive双速主减速器double gear (speed) final drive轮边减速器wheel reduction差速器differential半轴齿轮differential side gear差速锁differential lock轴间差速器inter-axle differential lock托森差速器torque sensitive differential半轴axle shaft全浮式半轴float type axle shaft半浮式半轴semi-float type axle shaft桥壳axle housing桥壳后盖final drive rear cover第十八章行驶系行驶系running gear车架frame车桥，车轴axle 悬架suspension半履带式汽车semi-caterpillar vehicle第十九章车架边梁式车架ladder typeframe纵梁side rail横梁cross member保险杠bumper托架bracket支承support拖钩tow hook中梁式车架backbone typeframe桁架式车架lattice typeframe第二十章车桥和车轮转向桥steering axle桥梁axle beam工字形断面I-section转向节knuckle主销king pin轮毂wheel hub转向轮定位steering wheelalignment主销后倾caster主销内倾king pininclination前轮外倾camber前轮前束toe-in转向驱动桥steering anddriving axle支持桥support axle轮辋rim轮辐spoke车轮装饰罩hub cap轮胎tyre, tire胎冠crown, tread花纹pattern胎侧side wall帘布层cord, ply尼龙，锦纶nylon带束层belted layer内胎tube垫带protector胎圈bead气门嘴bleed valve气门芯valve core子午线轮胎radial tire无内胎轮胎tubeless tire刺穿puncture备胎spare tire第二十一章悬架弹性元件spring, elasticelement减振器sock absorber导向机构control device横向稳定器（杆）stabilizer,anti-roll bar悬架刚度suspensionstiffness簧载质量sprung mass非簧载质量unsprung mass静挠度static deformation独立悬架independentsuspension车轮上跳（减振器压缩行程）jounce车轮回跳（减振器伸张行程）rebound双向作用减振器doubleaction shock absorber单向作用减振器singleaction shock absorber筒式减振器telescopicshock absorber吊环link ring工作缸working cylinder贮油缸reservoir流通阀（进液阀）intakevalve伸张阀rebound valve压缩阀compression valve补偿阀compensation valve充气减振器gas filled shockabsorber压力可调减振器pressureadjustable shock absorber钢板弹簧leaf spring中心螺栓central bolt弹簧夹clip螺旋弹簧coil spring扭杆弹簧torsional bar囊式空气弹簧bellow typeair spring膜式空气弹簧diaphragm type air spring橡胶弹簧rubber spring卷耳spring eye吊耳shackleU形螺栓U-bolt弹簧盖板spring plate副簧auxiliary spring主簧main spring横臂式悬架transversal typesuspension双横臂式悬架double wishbone suspension转向轴线steering axis纵摆臂式trailing arm type 滑柱式strut type麦弗逊式McPhaeson type 平衡悬架tandem axle suspension第二十二章转向系机械（手动）转向系manual steering system转向盘steering wheel转向轴steering shaft转向柱steering column转向传动轴steering drive shaft转向器steering gear直拉杆drag link转向节knuckle转向节臂knuckle arm梯形臂steering arm横拉杆tie rod转向轮偏转角关系steering geometry转弯半径turning radius循环球式转向器recirculating ball steeringgear转向螺杆steering screw转向螺母steering nut齿扇sector齿轮齿条式转向器rackand pinion steering gear蜗杆曲柄指销式转向器worm and crankpin steeringgear动力转向power steering转向油罐steering reservoir转向油泵steering oil pump第二十三章制动系鼓式制动器drum brake制动蹄brake shoe轮缸wheel cylinder制动底板brake base plate调整凸轮adjustable cam制动蹄回位弹簧retainerspring领蹄leading shoe从蹄trailing shoe盘式制动器disc brake制动钳brake calipers制动盘brake disc液压制动系fluid brakingsystem制动液brake fluid制动主缸master cylinder气压制动系pneumaticbraking system空气压缩机air compressor制动气室brake chamber贮气筒reservoir制动阀brake valve气压调节阀air pressuregovernor伺服制动系servo brakingsystem真空助力器vacuumbooster防抱死制动系(ABS)Anti-lock Braking System辅助制动器auxiliary brake缓速器retarder排气制动exhaust braking第二十四章车身车身壳体body shell非承载式车身separateframe construction承载式车身unitaryconstruction, integral body发动机舱enginecompartment客厢，乘客室passengercompartment行李箱trunk发动机罩hood, bonnet前翼板front fender, frontwing前挡泥板front fender apron前围板dash board, fire wall前风窗windscreen,windshield前围cowl, shroud顶盖roof地板floor panel行李箱盖trunk lid, deck lid后围板rear end panel前柱front pillar, “A”pillar中柱center pillar, “B”pillar后柱rear pillar, “C”pillar上边梁roof rail门槛rocker panel仪表板instrument panel遮阳板sun visor刮水器wiper后视镜rear view mirror门锁door lock玻璃升降器windowregulator密封条weather strip暖气装置heater空调装置air conditioner座椅seat头枕head restraint安全带safety seat belt钢化玻璃toughened glass 夹层玻璃laminated glass货箱carrying platform边板side board后板tail board前板head board地板，底板floor board栓杆tightening latch第二十五章附属设备车速表speedometer里程表mileage recorder机油压力表oil pressuregauge燃油表fuel gauge水温表water temperaturegauge电流表ammeter前大灯head lamp转向指示灯turning indicator制动信号灯braking signal light报警信号装置warning signal附表一般工程词汇长度length宽度width高度height深度depth距离distance间隙clearance位移displacement面积area体积volume重量weight质量mass比重specific gravity密度density时间time周期period加速度velocity, speed重力加速度acceleration of gravity力force合力resultant分力component力矩moment转矩torque, twistingmoment弯矩bending moment压强pressure大气压atmosphericpressure声压级(SPL) SoundPressure Level应力stress应变strain变形deformation拉伸stretching压缩compressing弯曲bending扭转twisting强度strength刚度stiffness硬度hardness黏度viscosity运动黏度kinematicviscosity能量energy动能kinetic energy位能potential energy功work功率power温度temperature热heat热容量thermal capacity比热specific heat热功当量Joule’sequivalent传热系数coefficient of heattransfer加热heating冷却cooling膨胀expansion固体solid液体liquid气体gas蒸发evaporation溶解dissolve融化melt凝结condensation凝固solidification电路electric circuit串联serial connection并联parallel connection电荷electric charge电压voltage电位potential电流current直流(D.C.) Direct Current交流(A.C.) AlternativeCurrent电阻resistance电容量capacity电容器condenser电感inductance电极electrode正极anode负极cathode电离ionization电解electrolysis电镀electroplating电泳electrophoresis磁场强度magnetic fieldintensity磁通量magnetic flux光通量luminous flux光照度photometricquantity发光强度luminousintensity工程图technical drawing图板drawing board图纸drawing paper描图纸tracing paper投影projection前视图front end view侧视图side view左视图left end view右视图right end view俯视图plan view剖面section剖视section view实线full line虚线broken line, dotted line 点划线chain line尺寸线dimension line方形square长方形rectangle三角形triangle圆形circle内接圆inscribed circle外切圆circumscribed circle 直尺ruler三棱尺triangular scale三角板set square丁字尺tee square, T square 圆规compasses分规divider曲线板curve鸭嘴笔drawing pen锤子hammer斧子ax, axe螺丝刀screw driver扳手wrench, spanner活动扳手adjustable wrench 扳手套筒socket钳子pliers火钳子tongs虎钳vice刀子knife刮刀scraper剪子scissors镊子tweezers夹子clip夹紧器clamp锉刀file凿子，錾子chisel冲子punch锥子awl锯子saw刨子plane钻drill砧铁anvil 直角尺square内卡规inside calipers外卡规outside calipers游标卡尺vernier calipers千分卡尺micrometer guage高度尺height gauge千分表dial indicator水平（泡）尺water level画针盘marking gauge螺纹threads螺栓bolt双头螺柱stud螺钉screw十字槽螺钉cross recessedscrew螺母nut开槽螺母castle nut蝶形螺母fly nut, wing nut垫圈washer弹簧垫圈lock washer开口销split pin, cotter pin键key花键spline直齿齿轮spur gear斜齿齿轮helical gear伞齿轮bevel gear球轴承ball bearing滚子轴承roller bearing滚针轴承needle rollerbearing轴承外圈outer race轴承内圈inner race隔离罩，保持架cage,retainer铸造，铸件casting锻造，锻件forging轧制，轧制件rolling冲压，冲压件stamping焊接，焊缝welding电弧焊arc welding气焊oxyacetylene welding点焊spot welding铆接，铆钉rivet机械加工machine work切削cutting车削turning刨削planing铣削milling钻削drilling绞孔fraising磨削grinding镗削boring拉削broaching抛光polishing热处理heat treatment淬火hardening, quenching退火annealing回火tempering正火normalizing车床lathe龙门刨床planer牛头刨床shaper插床vertical shaper铣床milling machine钻床drilling machine磨床grinder, grindingmachine外圆磨床external grinder内圆磨床internal grinder平面磨床surface grinder镗床boring machine拉床broacher床头箱head stock (gearbox)卡盘，夹盘chuck尾座tail stock走刀箱tool carrier模具die, mold气锤pneumatic hammer压床press刀具cutter车刀，刨刀bite铣刀，绞刀fraise钻头bite磨轮，砂轮grinding wheel夹具fixture, jig本文来自机械工程师家园：http://www.chinamachinis。

How Car Suspensions WorkTable of Contents:›Introduction to How Car Suspensions Work›Vehicle Dynamics›The Chassis›Springs›Springs: Sprung and Unsprung Mass›Dampers: Shock Absorbers›Dampers: Struts and Anti-sway Bars›Suspension Types: Front›Suspension Types: Rear›Specialized Suspensions: The Baja Bug›Specialized Suspensions: Formula One Racers›Specialized Suspensions: Hot Rods›The Future of Car Suspensions›Lots More Information›Compare Prices for Car SuspensionsWhen people think of automobile performance, they normally think of horsepower, torque and zero-to-60 acceleration. But all of the power generated by a piston engine is useless if the driver can't control the car. That's why automobile engineers turned their attention to the suspension system almost as soon as they had mastered the four-stroke internal combustion engine.Photo courtesy Honda Motor Co., Ltd.Double-wishbone suspension on Honda Accord 2005 CoupeThe job of a car suspension is to maximize the friction between the tires and the road surface, to provide steering stability with good handling and to ensure the comfort of the passengers. In this article, we'll explore how car suspensions work, how they've evolved over the years and where the design of suspensions is headed in the future.Vehicle Dynamics（汽车动力学）If a road were perfectly flat, with no irregularities, suspensions wouldn't be necessary. But roads are farfrom flat. Even freshly paved highways have subtle imperfections that can interact with the wheels of a car. It's these imperfections that apply forces to the wheels. According to Newton's laws of motion（牛顿运动理论）, all forces have both magnitude（大小）and direction. A bump（撞击）in the road causes the wheel to move up and down perpendicular（垂直的）to the road surface. The magnitude, of course, depends on whether the wheel is striking a giant bump or a tiny speck（斑点）. Either way, the car wheel experiences a vertical acceleration as it passes over an imperfection.Without an intervening（介入）structure, all of wheel's vertical energy is transferred to the frame, which moves in the same direction. In such a situation, the wheels can lose contact with the road completely. Then, under the downward force of gravity, the wheels can slam back into the road surface. What you need is a system that will absorb the energy of the vertically accelerated wheel, allowing the frame and body to ride undisturbed while the wheels follow bumps in the road.The study of the forces at work on a moving car is called vehicle dynamics, and you need to understand some of these concepts in order to appreciate why a suspension is necessary in the first place. Most automobile engineers consider the dynamics of a moving car from two perspectives:•Ride - a car's ability to smooth out a bumpy road•Handling - a car's ability to safely accelerate, brake and cornerThese two characteristics can be further described in three important principles - road isolation, road holding and cornering. The table below describes these principles and how engineers attempt to solve the challenges unique to each.Principle Definition Goal SolutionRoad Isolation The vehicle's ability toabsorb or isolate roadshock from thepassenger compartmentAllow the vehiclebody to rideundisturbed whiletraveling overrough roads.Absorb energyfrom roadbumps anddissipate（驱散）it withoutcausing undue（不恰当的）oscillation（振A car's suspension, with its various components, provides all of the solutions described.Let's look at the parts of a typical suspension, working from the bigger picture of the chassis down to the individual components that make up the suspension proper.The ChassisThe suspension of a car is actually part of the chassis, which comprises all of the important systems located beneath the car's body.ChassisThese systems include:•The frame - structural, load-carrying component that supports the car's engine and body, which are in turn supported by the suspension•The suspension system - setup that supports weight, absorbs and dampens shock and helps maintain tire contact•The steering system - mechanism that enables the driver to guide and direct the vehicle•The tires and wheels - components that make vehicle motion possible by way of grip and/or friction with the roadSo the suspension is just one of the major systems in any vehicle.With this big-picture overview in mind, it's time to look at the three fundamental components of any suspension: springs, dampers and anti-sway bars.SpringsToday's springing systems are based on one of four basic designs:•Coil springs - This is the most common type of spring and is, in essence, a heavy-duty torsion bar coiled around an axis. Coil springs compress and expand to absorb the motion of thewheels.Photo courtesy Car Domain Coil springs• Leaf springs - This type of spring consists ofseveral layers of metal (called "leaves") boundtogether to act as a single unit. Leaf springswere first used on horse-drawn carriages andwere found on most American automobiles until1985. They are still used today on most trucksand heavy-duty vehicles. • Torsion bars - Torsion bars （扭力杆） use the twisting properties of a steel bar to providecoil-spring-like performance. This is how they work: One end of a bar is anchored to the vehicleframe. The other end is attached to a wishbone, which acts like a lever that movesperpendicular to the torsion bar. When the wheel hits a bump, vertical motion is transferred tothe wishbone and then, through the levering action, to the torsion bar. The torsion bar thentwists along its axis to provide the spring force. European carmakers used this systemextensively, as did Packard and Chrysler in the United States, through the 1950s and 1960s.Photo courtesyHowStuffWorks ShopperTorsion bar• Air springs - Air springs, which consist of a cylindrical chamber of air positioned between thewheel and the car's body, use the compressive qualities of air to absorb wheel vibrations. Theconcept is actually more than a century old and could be found on horse-drawn buggies. Airsprings from this era were made from air-filled, leather diaphragms, much like a bellows; theywere replaced with molded-rubber （橡胶浇筑） air springs in the 1930s.Photo courtesy HowStuffWorks Shopper Leaf springPhoto courtesy HSW ShopperAir springsBased on where springs are located on a car -- i.e., between the wheels and the frame -- engineers often find it convenient to talk about the sprung mass and the unsprung mass.Springs: Sprung and Unsprung Mass（簧下质量）The sprung mass is the mass of the vehicle supported on the springs, while the unsprung mass is loosely defined as the mass between the road and the suspension springs. The stiffness of the springs affects how the sprung mass responds while the car is being driven. Loosely sprung cars, such as luxury cars (think Lincoln Town Car), can swallow bumps and provide a super-smooth ride; however, such a car is prone to dive and squat during braking and acceleration and tends to experience body sway or roll during cornering. Tightly sprung cars, such as sports cars (think Mazda Miata), are less forgiving on bumpy roads, but they minimize body motion well, which means they can be driven aggressively, even around corners.So, while springs by themselves seem like simple devices, designing and implementing them on a car to balance passenger comfort with handling is a complex task. And to make matters more complex, springs alone can't provide a perfectly smooth ride. Why? Because springs are great at absorbing energy, but not so good at dissipating it. Other structures, known as dampers, are required to do this.Dampers: Shock AbsorbersUnless a dampening structure is present, a car spring will extend and release the energy it absorbs froma bump at an uncontrolled rate. The spring will continue to bounce（反弹）at its natural frequency until all of the energy originally put into it is used up. A suspension built on springs alone would make for an extremely bouncy ride and, depending on the terrain, an uncontrollable car.Enter the shock absorber, or snubber（缓冲器）, a device that controls unwanted spring motion through a process known as dampening. Shock absorbers slow down and reduce the magnitude of vibratory motions by turning the kinetic energy （动能）of suspension movement into heat energy that can be dissipated through hydraulic fluid. To understand how this works, it's best to look inside a shock absorber to see its structure and function.A shock absorber is basically an oil pump placed between the frame of the car and the wheels. The upper mount of the shock connects to the frame (i.e., the sprung weight), while the lower mount connects to the axle, near the wheel (i.e., the unsprung weight). In a twin-tube design, one of the most common types of shock absorbers, the upper mount is connected to a piston rod, which in turn is connected to a piston, which in turn sits in a tube filled with hydraulic fluid. The inner tube is known as the pressure tube, and the outer tube is known as the reserve tube. The reserve tube stores excess hydraulic fluid.When the car wheel encounters a bump in the road and causes the spring to coil and uncoil, the energy of the spring is transferred to the shock absorber through the upper mount, down through the piston rod and into the piston. Orifices perforate the piston and allow fluid to leak through as the piston moves upand down in the pressure tube. Because the orifices are relatively tiny, only a small amount of fluid, under great pressure, passes through. This slows down the piston, which in turn slows down the spring.Shock absorbers work in two cycles -- the compression cycle and the extension cycle. The compression cycle occurs as the piston moves downward, compressing the hydraulic fluid in the chamber below the piston. The extension cycle occurs as the piston moves toward the top of the pressure tube, compressing the fluid in the chamber above the piston. A typical car or light truck will have more resistance during its extension cycle than its compression cycle. With that in mind, the compression cycle controls the motion of the vehicle's unsprung weight, while extension controls the heavier, sprung weight.All modern shock absorbers are velocity-sensitive -- the faster the suspension moves, the more resistance the shock absorber provides. This enables shocks to adjust to road conditions and to control all of the unwanted motions that can occur in a moving vehicle, including bounce, sway, brake dive and acceleration squat.Dampers: Struts and Anti-sway BarsAnother common dampening structure is the strut -- basically a shock absorber mounted inside a coil spring. Struts perform two jobs: They provide a dampening function like shock absorbers, and they provide structural support for the vehicle suspension. That means struts deliver a bit more than shock absorbers, which don't support vehicle weight -- they only control the speed at which weight is transferred in a car, not the weight itself.Common strut designBecause shocks and struts have so much to do with the handling of a car, they can be considered critical safety features. Worn shocks and struts can allow excessive vehicle-weight transfer from side to side and front to back. This reduces the tire's ability to grip the road, as well as handling and braking performance.Anti-sway Bars（稳定杆）Anti-sway bars (also known as anti-roll bars) are used along with shock absorbers or struts to give a moving automobile additional stability. An anti-sway bar is a metal rod that spans the entire axle and effectively joins each side of the suspension together.Photo courtesy HSW ShopperAnti-sway barsWhen the suspension at one wheel moves up and down, the anti-sway bar transfers movement to the other wheel. This creates a more level ride and reduces vehicle sway. In particular, it combats the roll of a car on its suspension as it corners. For this reason, almost all cars today are fitted with anti-sway bars as standard equipment, although if they're not, kits make it easy to install the bars at any time.Suspension Types: FrontSo far, our discussions have focused on how springs and dampers function on any given wheel. But the four wheels of a car work together in two independent systems -- the two wheels connected by the front axle and the two wheels connected by the rear axle. That means that a car can and usually does have a different type of suspension on the front and back. Much is determined by whether a rigid axle binds the wheels or if the wheels are permitted to move independently. The former arrangement is known as a dependent system, while the latter arrangement is known as an independent system. In the following sections, we'll look at some of the common types of front and back suspensions typically used on mainstream cars.Front Suspension - Dependent SystemsDependent front suspensions have a rigid front axle that connects the front wheels. Basically, this looks like a solid bar under the front of the car, kept in place by leaf springs and shock absorbers. Common on trucks, dependent front suspensions haven't been used in mainstream cars for years.Front Suspension - Independent SystemsIn this setup, the front wheels are allowed to move independently. The MacPherson strut, developed by Earle S. MacPherson of General Motors in 1947, is the most widely used front suspension system, especially in cars of European origin.The MacPherson strut combines a shock absorber and a coil spring into a single unit. This provides a more compact and lighter suspension system that can be used for front-wheel drive vehicles.The double-wishbone suspension, also known as an A-arm suspension, is another common type of front independent suspension.Photo courtesy Honda Motor Co., Ltd.Double-wishbone suspension on Honda Accord 2005 CoupeWhile there are several different possible configurations, this design typically uses two wishbone-shaped arms to locate the wheel. Each wishbone, which has two mounting positions to the frame and one at the wheel, bears a shock absorber and a coil spring to absorb vibrations. Double-wishbone suspensions allow for more control over the camber angle of the wheel, which describes the degree to which thewheels tilt in and out. They also help minimize roll or sway and provide for a more consistent steering feel. Because of these characteristics, the double-wishbone suspension is common on the front wheels of larger cars.Now let's look at some common rear suspensions.Suspension Types: RearRear Suspension - Dependent SystemsIf a solid axle connects the rear wheels of a car, then thesuspension is usually quite simple -- based either on a leaf springor a coil spring. In the former design, the leaf springs clampdirectly to the drive axle. The ends of the leaf springs attachdirectly to the frame, and the shock absorber is attached at theclamp that holds the spring to the axle. For many years, Americancar manufacturers preferred this design because of its simplicity.The same basic design can be achieved with coil springs replacing the leaves. In this case, the spring and shock absorber can be mounted as a single unit or as separate components. When they're separate, the springs can be much smaller, which reduces the amount of space the suspension takes up. Rear Suspension - Independent SuspensionsIf both the front and back suspensions are independent, then all of the wheels are mounted and sprung individually, resulting in what car advertisements tout as "four-wheel independent suspension." Any suspension that can be used on the front of the car can be used on the rear, and versions of the front independent systems described in the previous section can be found on the rear axles. Of course, in the Photo courtesy HowStuffWorks Shopper Leaf springrear of the car, the steering rack -- the assembly that includes the pinion gear wheel and enables the wheels to turn from side to side -- is absent. This means that rear independent suspensions can be simplified versions of front ones, although the basic principles remain the same.Specialized Suspensions: The Baja BugFor the most part, this article has focused on the suspensions of mainstream front- and rear-wheel-drive cars -- cars that drive on normal roads in normal driving conditions. But what about the suspensions of specialty cars, such as hot rods, racers or extreme off-road vehicles? Although the suspensions of specialty autos obey the same basic principles, they do provide additional benefits unique to the driving conditions they must navigate. What follows is a brief overview of how suspensions are designed for three types of specialty cars -- Baja Bugs, Formula One racers and American-style hot rods.Baja BugsThe Volkswagen Beetle or Bug was destined to become a favorite among off-road enthusiasts. With a low center of gravity and engine placement over the rear axle, the two-wheel-drive Bug handles off-road conditions as well as some four-wheel-drive vehicles. Of course, the VW Bug isn't ready for off-road conditions with its factory equipment. Most Bugs require some modifications, or conversions, to get them ready for racing in harsh conditions like the deserts of Baja California.Photo courtesy Car DomainBaja BugOne of the most important modifications takes place in the suspension. The torsion-bar suspension, standard equipment on the front and back of most Bugs between 1936 and 1977, can be raised to make room for heavy-duty, off-road wheels and tires. Longer shock absorbers replace the standard shocks to lift the body higher and to provide for maximum wheel travel. In some cases, Baja Bug converters remove the torsion bars entirely and replace them with multiple coil-over systems, an aftermarket item that combines both the spring and shock absorber in one adjustable unit. The result of these modifications is a vehicle that allows the wheels to travel vertically 20 inches (50 cm) or more at each end.Such a car can easily navigate rough terrain and often appears to "skip" over desert washboard like a stone over water.Specialized Suspensions: Formula One RacersThe Formula One racing car represents the pinnacle of automobile innovation and evolution. Lightweight, composite bodies, powerful V10 engines and advanced aerodynamics have led to faster, safer and more reliable cars.Formula One racecarTo elevate driver skill as the key differentiating factor in a race, stringent rules and requirements govern Formula One racecar design. For example, the rules regulating suspension design say that all Formula One racers must be conventionally sprung, but they don't allow computer-controlled, active suspensions. To accommodate this, the cars feature multi-link suspensions, which use a multi-rod mechanism equivalent to a double-wishbone system.Recall that a double-wishbone design uses two wishbone-shaped control arms to guide each wheel'sup-and-down motion. Each arm has three mounting positions -- two at the frame and one at the wheel hub -- and each joint is hinged to guide the wheel's motion. In all cars, the primary benefit of adouble-wishbone suspension is control. The geometry of the arms and the elasticity of the joints give engineers ultimate control over the angle of the wheel and other vehicle dynamics, such as lift, squat and dive. Unlike road cars, however, the shock absorbers and coil springs of a Formula One racecar don't mount directly to the control arms. Instead, they are oriented along the length of the car and are controlled remotely through a series of pushrods and bell cranks. In such an arrangement, the pushrods and bell cranks translate the up-and-down motions of the wheel to the back-and-forth movement of the spring-and-damper apparatus.Specialized Suspensions: Hot RodsThe classic American hot rod era lasted from 1945 to about 1965. Like Baja Bugs, classic hot rods required significant modification by their owners. Unlike Bugs, however, which are built on Volkswagenchassis, hot rods were built on a variety of old, often historical, car models: Cars manufactured before 1945 were considered ideal fodder for hot rod transformations because their bodies and frames were often in good shape, while their engines and transmissions needed to be replaced completely. For hot rod enthusiasts, this was exactly what they wanted, for it allowed them to install more reliable and powerful engines, such as the flathead Ford V8 or the Chevrolet V8.Photo courtesy Street Rod Central1923 T-bucketOne popular hot rod was known as the T-bucket because it was based on the Ford Model T. The stock Ford suspension on the front of the Model T consisted of a solid I-beam front axle (a dependent suspension), a U-shaped buggy spring (leaf spring) and a wishbone-shaped radius rod with a ball at the rear end that pivoted in a cup attached to the transmission. Ford's engineers built the Model T to ride high with a large amount of suspension movement, an ideal design for the rough, primitive roads of the 1930s. But after World War II, hot rodders began experimenting with larger Cadillac or Lincoln engines, which meant that the wishbone-shaped radius rod was no longer applicable. Instead, they removed the center ball and bolted the ends of the wishbone to the framerails. This "split wishbone" design lowered the front axle about 1 inch (2.5 cm) and improved vehicle handling.Lowering the axle more than an inch required a brand-new design, which was supplied by a company known as Bell Auto. Throughout the 1940s and 1950s, Bell Auto offered dropped tube axles that lowered the car a full 5 inches (13 cm). Tube axles were built from smooth, steel tubing and balanced strength with superb aerodynamics. The steel surface also accepted chrome plating better than the forged I-beam axles, so hot rodders often preferred them for their aesthetic qualities, as well.Some hot rod enthusiasts, however, argued that the tube axle's rigidity and inability to flex compromised how it handled the stresses of driving. To accommodate this, hot rodders introduced the four-bar suspension, using two mounting points on the axle and two on the frame. At each mounting point, aircraft-style rod ends provided plenty of movement at all angles. The result? The four-bar system improved how the suspension worked in all sorts of driving conditions.The Future of Car SuspensionsWhile there have been enhancements and improvements to both springs and shock absorbers, the basic design of car suspensions has not undergone a significant evolution over the years. But all of that's about to change with the introduction of a brand-new suspension design conceived by Bose -- the same Bose known for its innovations in acoustic technologies. Some experts are going so far as to say that the Bose suspension is the biggest advance in automobile suspensions since the introduction of anall-independent design.Photo courtesy BOSEBose?Suspension Front ModuleHow does it work? The Bose system uses a linear electromagnetic motor (LEM) at each wheel in lieu of a conventional shock-and-spring setup. Amplifiers provide electricity to the motors in such a way that their power is regenerated with each compression of the system. The main benefit of the motors is that they are not limited by the inertia inherent in conventional fluid-based dampers. As a result, an LEM can extend and compress at a much greater speed, virtually eliminating all vibrations in the passenger cabin. The wheel's motion can be so finely controlled that the body of the car remains level regardless of what's happening at the wheel. The LEM can also counteract the body motion of the car while accelerating, braking and cornering, giving the driver a greater sense of control.Unfortunately, this paradigm（范例）-shifting suspension won't be available until 2009, when it will be offered on one or more high-end luxury cars. Until then, drivers will have to rely on the tried-and-true suspension methods that have smoothed out bumpy rides for centuries.For more information on car suspensions and related topics, check out the links on the next page.。

How Car Suspensions WorkTable of Contents:› Introduction to How Car Suspensions Work› Vehicle Dynamics› The Chassis› Springs› Springs: Sprung and Unsprung Mass› Dampers: Shock Absorbers› Dampers: Struts and Anti-sway Bars› Suspension Types: Front› Suspension Types: Rear› Specialized Suspensions: The Baja Bug› Specialized Suspensions: Formula One Racers› Specialized Suspensions: Hot Rods› The Future of Car Suspensions› Lots More Information› Compare Prices for Car SuspensionsWhen people think of automobile performance, they normally think of horsepower, torque and zero-to-60 acceleration. But all of the power generated by a piston engine is useless if the driver can't control the car. That's why automobile engineers turned their attention to the suspension system almost as soon as they had mastered the four-stroke internal combustion engine.Photo courtesy Honda Motor Co., Ltd.Double-wishbone suspension on Honda Accord 2005 CoupeThe job of a car suspension is to maximize the friction between the tires and the road surface, to provide steering stability with good handling and to ensure the comfort of the passengers. In this article, we'll explore how car suspensions work, how they've evolved over the years and where the design of suspensions is headed in the future.Vehicle Dynamics（汽车动力学）If a road were perfectly flat, with no irregularities, suspensions wouldn't be necessary. But roads are far from flat. Even freshly paved highways have subtle imperfections that can interact with the wheels of a car. It's these imperfections that apply forces to the wheels. According to Newton's laws of motion（牛顿运动理论）, all forces have both magnitude（大小） and direction.A bump（撞击）in the road causes the wheel to move up and down perpendicular（垂直的） to the road surface. The magnitude, of course, depends on whether the wheel is striking a giant bump or a tiny speck（斑点）. Either way, the car wheel experiences a vertical acceleration as it passes over an imperfection.Without an intervening（介入） structure, all of wheel's vertical energy is transferred to the frame, which moves in the same direction. In such a situation, the wheels can lose contact with the road completely. Then, under the downward force of gravity, the wheels can slam back into the road surface. What you need is a system that will absorb the energy of the vertically accelerated wheel, allowing the frame and body to ride undisturbed while the wheels follow bumps in the road.The study of the forces at work on a moving car is called vehicle dynamics, and you need to understand some of these concepts in order to appreciate why a suspension is necessary in the first place. Most automobile engineers consider the dynamics of a moving car from two perspectives:•Ride - a car's ability to smooth out a bumpy road•Handling - a car's ability to safely accelerate, brake and cornerThese two characteristics can be further described in three important principles - road isolation, road holding and cornering. The table below describes these principles and how engineers attempt to solve the challenges unique to each.Principle Definition Goal SolutionRoad Isolation The vehicle's abilityto absorb or isolateAllow thevehicle body toAbsorb energyfrom road bumpsA car's suspension, with its various components, provides all of the solutions described.Let's look at the parts of a typical suspension, working from the bigger picture of the chassis down to the individual components that make up the suspension proper.The ChassisThe suspension of a car is actually part of the chassis, which comprises all of the important systems located beneath the car's body.ChassisThese systems include:•The frame- structural, load-carrying component that supports the car's engine and body, which are in turn supported by the suspension•The suspension system - setup that supports weight, absorbs and dampens shock and helps maintain tire contact•The steering system - mechanism that enables the driver to guide and direct the vehicle •The tires and wheels- components that make vehicle motion possible by way of grip and/or friction with the roadSo the suspension is just one of the major systems in any vehicle.With this big-picture overview in mind, it's time to look at the three fundamental components of any suspension: springs, dampers and anti-sway bars.SpringsToday's springing systems are based on one of four basic designs:• Coil springs - This is the most common type of spring and is, in essence, a heavy-dutytorsion bar coiled around an axis. Coil springs compress and expand to absorb the motionof the wheels.Photo courtesy Car DomainCoil springs• Leaf springs - This type of spring consistsof several layers of metal (called "leaves")bound together to act as a single unit. Leafsprings were first used on horse-drawncarriages and were found on most American automobiles until 1985. They are still used today on most trucks and heavy-duty vehicles. • Torsion bars - Torsion bars （扭力杆） use the twisting properties of a steel bar to providecoil-spring-like performance. This is how they work: One end of a bar is anchored to the vehicle frame. The other end is attached to a wishbone, which acts like a lever that moves perpendicular to the torsion bar. When the wheel hits a bump, vertical motion istransferred to the wishbone and then, through the levering action, to the torsion bar. The torsion bar then twists along its axis to provide the spring force. European carmakers used this system extensively, as did Packard and Chrysler in the United States, through the 1950s and 1960s.Photo courtesy HowStuffWorks Shopper Leaf springPhoto courtesy HowStuffWorks ShopperTorsion bar•Air springs- Air springs, which consist of a cylindrical chamber of air positioned between the wheel and the car's body, use the compressive qualities of air to absorb wheelvibrations. The concept is actually more than a century old and could be found onhorse-drawn buggies. Air springs from this era were made from air-filled, leatherdiaphragms, much like a bellows; they were replaced with molded-rubber（橡胶浇筑） air springs in the 1930s.Photo courtesy HSW ShopperAir springsBased on where springs are located on a car -- i.e., between the wheels and the frame -- engineers often find it convenient to talk about the sprung mass and the unsprung mass.Springs: Sprung and Unsprung Mass（簧下质量）The sprung mass is the mass of the vehicle supported on the springs, while the unsprung mass is loosely defined as the mass between the road and the suspension springs. The stiffness of the springs affects how the sprung mass responds while the car is being driven. Loosely sprung cars, such as luxury cars (think Lincoln Town Car), can swallow bumps and provide a super-smooth ride; however, such a car is prone to dive and squat during braking and acceleration and tends to experience body sway or roll during cornering. Tightly sprung cars, such as sports cars (thinkMazda Miata), are less forgiving on bumpy roads, but they minimize body motion well, which means they can be driven aggressively, even around corners.So, while springs by themselves seem like simple devices, designing and implementing them on a car to balance passenger comfort with handling is a complex task. And to make matters more complex, springs alone can't provide a perfectly smooth ride. Why? Because springs are great at absorbing energy, but not so good at dissipating it. Other structures, known as dampers, are required to do this.Dampers: Shock AbsorbersUnless a dampening structure is present, a car spring will extend and release the energy it absorbs from a bump at an uncontrolled rate. The spring will continue to bounce（反弹） at its natural frequency until all of the energy originally put into it is used up. A suspension built on springs alone would make for an extremely bouncy ride and, depending on the terrain, an uncontrollable car.Enter the shock absorber, or snubber（缓冲器）, a device that controls unwanted spring motion through a process known as dampening. Shock absorbers slow down and reduce the magnitude of vibratory motions by turning the kinetic energy （动能）of suspension movement into heat energy that can be dissipated through hydraulic fluid. To understand how this works, it's best to look inside a shock absorber to see its structure and function.A shock absorber is basically an oil pump placed between the frame of the car and the wheels. The upper mount of the shock connects to the frame (i.e., the sprung weight), while the lower mount connects to the axle, near the wheel (i.e., the unsprung weight). In a twin-tube design, one of the most common types of shock absorbers, the upper mount is connected to a piston rod, which in turn is connected to a piston, which in turn sits in a tube filled with hydraulic fluid. The inner tube is known as the pressure tube, and the outer tube is known as the reserve tube. The reserve tube stores excess hydraulic fluid.When the car wheel encounters a bump in the road and causes the spring to coil and uncoil, the energy of the spring is transferred to the shock absorber through the upper mount, down through the piston rod and into the piston. Orifices perforate the piston and allow fluid to leak through as the piston moves up and down in the pressure tube. Because the orifices are relatively tiny, only a small amount of fluid, under great pressure, passes through. This slows down the piston, which in turn slows down the spring.Shock absorbers work in two cycles -- the compression cycle and the extension cycle. The compression cycle occurs as the piston moves downward, compressing the hydraulic fluid in the chamber below the piston. The extension cycle occurs as the piston moves toward the top of the pressure tube, compressing the fluid in the chamber above the piston. A typical car or light truck will have more resistance during its extension cycle than its compression cycle. With that inmind, the compression cycle controls the motion of the vehicle's unsprung weight, while extension controls the heavier, sprung weight.All modern shock absorbers are velocity-sensitive -- the faster the suspension moves, the more resistance the shock absorber provides. This enables shocks to adjust to road conditions and to control all of the unwanted motions that can occur in a moving vehicle, including bounce, sway, brake dive and acceleration squat.Dampers: Struts and Anti-sway BarsAnother common dampening structure is the strut -- basically a shock absorber mounted inside a coil spring. Struts perform two jobs: They provide a dampening function like shock absorbers, and they provide structural support for the vehicle suspension. That means struts deliver a bit more than shock absorbers, which don't support vehicle weight -- they only control the speed at which weight is transferred in a car, not the weight itself.Common strut designBecause shocks and struts have so much to do with the handling of a car, they can be considered critical safety features. Worn shocks and struts can allow excessive vehicle-weight transfer from side to side and front to back. This reduces the tire's ability to grip the road, as well as handling and braking performance.Anti-sway Bars（稳定杆）Anti-sway bars (also known as anti-roll bars) are used along with shock absorbers or struts to give a moving automobile additional stability. An anti-sway bar is a metal rod that spans the entire axle and effectively joins each side of the suspension together.Photo courtesy HSW ShopperAnti-sway barsWhen the suspension at one wheel moves up and down, the anti-sway bar transfers movement to the other wheel. This creates a more level ride and reduces vehicle sway. In particular, it combats the roll of a car on its suspension as it corners. For this reason, almost all cars today are fitted with anti-sway bars as standard equipment, although if they're not, kits make it easy to install the bars at any time.Suspension Types: FrontSo far, our discussions have focused on how springs and dampers function on any given wheel. But the four wheels of a car work together in two independent systems -- the two wheels connected by the front axle and the two wheels connected by the rear axle. That means that a car can and usually does have a different type of suspension on the front and back. Much is determined by whether a rigid axle binds the wheels or if the wheels are permitted to move independently. The former arrangement is known as a dependent system, while the latter arrangement is known as an independent system. In the following sections, we'll look at some of the common types of front and back suspensions typically used on mainstream cars.Front Suspension - Dependent SystemsDependent front suspensions have a rigid front axle that connects the front wheels. Basically, this looks like a solid bar under the front of the car, kept in place by leaf springs and shock absorbers. Common on trucks, dependent front suspensions haven't been used in mainstream cars for years.Front Suspension - Independent SystemsIn this setup, the front wheels are allowed to move independently. The MacPherson strut, developed by Earle S. MacPherson of General Motors in 1947, is the most widely used front suspension system, especially in cars of European origin.The MacPherson strut combines a shock absorber and a coil spring into a single unit. This provides a more compact and lighter suspension system that can be used for front-wheel drive vehicles.The double-wishbone suspension, also known as an A-arm suspension, is another common type of front independent suspension.Photo courtesy Honda Motor Co., Ltd.Double-wishbone suspension on Honda Accord 2005 CoupeWhile there are several different possible configurations, this design typically uses two wishbone-shaped arms to locate the wheel. Each wishbone, which has two mounting positions to the frame and one at the wheel, bears a shock absorber and a coil spring to absorb vibrations. Double-wishbone suspensions allow for more control over the camber angle of the wheel, which describes the degree to which the wheels tilt in and out. They also help minimize roll or sway and provide for a more consistent steering feel. Because of these characteristics, the double-wishbone suspension is common on the front wheels of larger cars.Now let's look at some common rear suspensions.Suspension Types: RearRear Suspension - Dependent SystemsIf a solid axle connects the rear wheels of a car, then thesuspension is usually quite simple -- based either on a leaf spring or a coil spring. In the former design, the leaf springsclamp directly to the drive axle. The ends of the leaf springsattach directly to the frame, and the shock absorber is attached at the clamp that holds the spring to the axle. For many years, American car manufacturers preferred this design because of its simplicity.The same basic design can be achieved with coil springs replacing the leaves. In this case, the spring and shock absorber can be mounted as a single unit or as separate components. When they're separate, the springs can be much smaller, which reduces the amount of space the suspension takes up. Rear Suspension - Independent SuspensionsIf both the front and back suspensions are independent, then all of the wheels are mounted and sprung individually, resulting in what car advertisements tout as "four-wheel independent suspension." Any suspension that can be used on the front of the car can be used on the rear, and versions of the front independent systems described in the previous section can be found on the rear axles. Of course, in the rear of the car, the steering rack -- the assembly that includes the pinion gear wheel and enables the wheels to turn from side to side -- is absent. This means that rear independent suspensions can be simplified versions of front ones, although the basic principles remain the same.Specialized Suspensions: The Baja BugFor the most part, this article has focused on the suspensions of mainstream front- andPhoto courtesy HowStuffWorks Shopper Leaf springrear-wheel-drive cars -- cars that drive on normal roads in normal driving conditions. But what about the suspensions of specialty cars, such as hot rods, racers or extreme off-road vehicles? Although the suspensions of specialty autos obey the same basic principles, they do provide additional benefits unique to the driving conditions they must navigate. What follows is a brief overview of how suspensions are designed for three types of specialty cars -- Baja Bugs, Formula One racers and American-style hot rods.Baja BugsThe Volkswagen Beetle or Bug was destined to become a favorite among off-road enthusiasts. With a low center of gravity and engine placement over the rear axle, the two-wheel-drive Bug handles off-road conditions as well as some four-wheel-drive vehicles. Of course, the VW Bug isn't ready for off-road conditions with its factory equipment. Most Bugs require some modifications, or conversions, to get them ready for racing in harsh conditions like the deserts of Baja California.Photo courtesy Car DomainBaja BugOne of the most important modifications takes place in the suspension. The torsion-bar suspension, standard equipment on the front and back of most Bugs between 1936 and 1977, can be raised to make room for heavy-duty, off-road wheels and tires. Longer shock absorbers replace the standard shocks to lift the body higher and to provide for maximum wheel travel. In some cases, Baja Bug converters remove the torsion bars entirely and replace them with multiple coil-over systems, an aftermarket item that combines both the spring and shock absorber in one adjustable unit. The result of these modifications is a vehicle that allows the wheels to travel vertically 20 inches (50 cm) or more at each end. Such a car can easily navigate rough terrain and often appears to "skip" over desert washboard like a stone over water.Specialized Suspensions: Formula One RacersThe Formula One racing car represents the pinnacle of automobile innovation and evolution. Lightweight, composite bodies, powerful V10 engines and advanced aerodynamics have led to faster, safer and more reliable cars.Formula One racecarTo elevate driver skill as the key differentiating factor in a race, stringent rules and requirements govern Formula One racecar design. For example, the rules regulating suspension design say that all Formula One racers must be conventionally sprung, but they don't allow computer-controlled, active suspensions. To accommodate this, the cars feature multi-link suspensions, which use a multi-rod mechanism equivalent to a double-wishbone system.Recall that a double-wishbone design uses two wishbone-shaped control arms to guide each wheel's up-and-down motion. Each arm has three mounting positions -- two at the frame and one at the wheel hub -- and each joint is hinged to guide the wheel's motion. In all cars, the primary benefit of a double-wishbone suspension is control. The geometry of the arms and the elasticity of the joints give engineers ultimate control over the angle of the wheel and other vehicle dynamics, such as lift, squat and dive. Unlike road cars, however, the shock absorbers and coil springs of a Formula One racecar don't mount directly to the control arms. Instead, they are oriented along the length of the car and are controlled remotely through a series of pushrods and bell cranks. In such an arrangement, the pushrods and bell cranks translate the up-and-down motions of the wheel to the back-and-forth movement of the spring-and-damper apparatus.Specialized Suspensions: Hot RodsThe classic American hot rod era lasted from 1945 to about 1965. Like Baja Bugs, classic hot rods required significant modification by their owners. Unlike Bugs, however, which are built on Volkswagen chassis, hot rods were built on a variety of old, often historical, car models: Cars manufactured before 1945 were considered ideal fodder for hot rod transformations because theirbodies and frames were often in good shape, while their engines and transmissions needed to be replaced completely. For hot rod enthusiasts, this was exactly what they wanted, for it allowed them to install more reliable and powerful engines, such as the flathead Ford V8 or the Chevrolet V8.Photo courtesy Street Rod Central1923 T-bucketOne popular hot rod was known as the T-bucket because it was based on the Ford Model T. The stock Ford suspension on the front of the Model T consisted of a solid I-beam front axle (a dependent suspension), a U-shaped buggy spring (leaf spring) and a wishbone-shaped radius rod with a ball at the rear end that pivoted in a cup attached to the transmission. Ford's engineers built the Model T to ride high with a large amount of suspension movement, an ideal design for the rough, primitive roads of the 1930s. But after World War II, hot rodders began experimenting with larger Cadillac or Lincoln engines, which meant that the wishbone-shaped radius rod was no longer applicable. Instead, they removed the center ball and bolted the ends of the wishbone to the framerails. This "split wishbone" design lowered the front axle about 1 inch (2.5 cm) and improved vehicle handling.Lowering the axle more than an inch required a brand-new design, which was supplied by a company known as Bell Auto. Throughout the 1940s and 1950s, Bell Auto offered dropped tube axles that lowered the car a full 5 inches (13 cm). Tube axles were built from smooth, steel tubing and balanced strength with superb aerodynamics. The steel surface also accepted chrome plating better than the forged I-beam axles, so hot rodders often preferred them for their aesthetic qualities, as well.Some hot rod enthusiasts, however, argued that the tube axle's rigidity and inability to flex compromised how it handled the stresses of driving. To accommodate this, hot rodders introduced the four-bar suspension, using two mounting points on the axle and two on the frame. At each mounting point, aircraft-style rod ends provided plenty of movement at all angles. The result? The four-bar system improved how the suspension worked in all sorts of driving conditions.The Future of Car SuspensionsWhile there have been enhancements and improvements to both springs and shock absorbers, the basic design of car suspensions has not undergone a significant evolution over the years. But all of that's about to change with the introduction of a brand-new suspension design conceived by Bose -- the same Bose known for its innovations in acoustic technologies. Some experts are going so far as to say that the Bose suspension is the biggest advance in automobile suspensions since the introduction of an all-independent design.Photo courtesy BOSEBose?Suspension Front ModuleHow does it work? The Bose system uses a linear electromagnetic motor(LEM) at each wheel in lieu of a conventional shock-and-spring setup. Amplifiers provide electricity to the motors in such a way that their power is regenerated with each compression of the system. The main benefit of the motors is that they are not limited by the inertia inherent in conventional fluid-based dampers. As a result, an LEM can extend and compress at a much greater speed, virtually eliminating all vibrations in the passenger cabin. The wheel's motion can be so finely controlled that the body of the car remains level regardless of what's happening at the wheel. The LEM can also counteract the body motion of the car while accelerating, braking and cornering, giving the driver a greater sense of control.Unfortunately, this paradigm（范例）-shifting suspension won't be available until 2009, when it will be offered on one or more high-end luxury cars. Until then, drivers will have to rely on the tried-and-true suspension methods that have smoothed out bumpy rides for centuries.For more information on car suspensions and related topics, check out the links on the next page.。